1. Field of the Invention
The invention is drawn to a method for controlling the odor emissions from animal waste.
2. Description of the Prior Art
Swine and other livestock are commonly reared in facilities that are specially designed to manage manure and liquid waste generated by such livestock. For example, in some swine rearing facilities, swine are raised in enclosed facilities that have slatted floors. Beneath the floors are pits for receiving swine manure and urine that pass through the slatted floor. These pits contain water that is occasionally drained to remove the livestock waste. Other facilities raise swine on a hard slanted floor, and periodically wash accumulated manure and urine from the slanted floor. Still other facilities use a combined approach, and have slatted floors on which the swine are raised, and a slanted floor underneath that is periodically washed to remove accumulated manure and urine. Water that is used to flush manure in these facilities is often pumped into large tanks that can be quickly discharged to rapidly flush manure from the facility.
Dairy cows are also often raised in facilities that must periodically be washed of animal manure and urine. The dairy cows are often fed in a sheltered pen that has a hard concrete floor that is periodically washed.
Manure excreted by the livestock generate hydrogen sulfide, methane, ammonia, volatile fatty acids, phenols, and other gases that contribute to the offensive odor in many livestock rearing facilities. The emitted hydrogen sulfide can also pose a health risk to workers as well as the animals. Hydrogen sulfide is being considered as a regulatory standard to monitor emissions from swine facilities. Production of H2S involves sulfate reduction largely by anaerobic sulfate-reducing bacteria (SRB). Previous studies by Cook et al. (for example, 2004, Detection of Sulfate-Reducing Bacteria in Stored Swine Manure Using Quantitative Real-Time PCR Analysis, Microbial Ecology International Symposium paper no. 2260) and Whitehead et al. (for example, 2004, Pure Culture and PCR Analyses of Sulfate-Reducing Bacteria from Swine Feces and Stored Swine Manure, Reproduction Nutrition Development 44:S32) began to uncover the diversity of SRB in stored swine manure using a phylogenetic and molecular based approach. Phylogenetic analysis of cloned dissimilitory sulfite reductase A (dsrA) genes identified 3 major groups of SRB in swine manure with high similarity to Desulfobulbus and Desulfovibrio-like species.
Numerous management strategies, technologies, and chemicals have been used to try to reduce these gases. However, many of these are usually either too toxic to the animals, not cost effective or not environmentally sustainable. Thus, the need remains for improved techniques for reducing offensive odors generated from animal wastes.